Operation not permitted (NSPOSIXErrorDomain:1)

When I had OS X 10.4.1, I used to use safari to right-click and click open new tab links such as "file:///Volumes/Drive1/Folder1" and it would open the directory in finder for me.

However, since I've moved over to 10.5.5, I get the following error "Operation could not be completed. Operation not permitted(NSPOSIXErrorDomain:1)" in Safari.

I am able to use "file:///Volumes" to access my volumes but after that I am unable to access.

My other Mac which is still running 10.4.1 does not have this issue however I've noted the following which may or may not be relevant.

Mac 1 has OS X 10.5.5 which has this problem is bundled with Safari 3.1.2 (5525.20.1)
Mac 2 OS X 10.4.1 which works fine is bundled with Safari 3.1.2 (5525.22)

Also this occurs in firefox as well.

I appreciate any feedback you can give me,

Thanks